• Keneitsino Lydia
• June 3, 2026

Master Allergy and Hypersensitivity MCQs Biology with Answers – Essential Questions for Exam Success

Allergy and Hypersensitivity MCQs Biology with Answers is an important topic for aspirants who want to understand immune reactions, allergic responses, antibodies, mast cells, histamine, inflammation, and hypersensitivity in a clear and exam-focused way. Allergy and Hypersensitivity MCQs Biology with Answers helps aspirants revise how the immune system sometimes reacts excessively to harmless substances such as pollen, dust, food particles, insect bites, medicines, or environmental pollutants.

In biology, allergy is explained as an exaggerated immune response, while hypersensitivity refers to an abnormal or overactive immune reaction that may damage body tissues. Allergy and Hypersensitivity MCQs Biology with Answers is useful for Class 12 Biology, NEET, nursing, medical entrance, and other competitive exam preparation because this topic connects immunity with real-life health conditions.

Allergy and Hypersensitivity MCQs Biology with Answers becomes easier when aspirants first understand the role of allergens. Allergens are substances that trigger allergic reactions in sensitive individuals. Common allergens include dust mites, pollen grains, animal dander, certain foods, drugs, and fungal spores. Allergy and Hypersensitivity MCQs Biology with Answers helps aspirants remember that allergic reactions are usually mediated by IgE antibodies. When an allergen enters the body, IgE antibodies bind to mast cells and basophils. On repeated exposure, these cells release chemicals such as histamine, serotonin, and other inflammatory mediators. Allergy and Hypersensitivity MCQs Biology with Answers therefore explains why symptoms such as sneezing, watery eyes, itching, swelling, redness, running nose, and breathing difficulty occur during allergy.

Aspirants preparing Allergy and Hypersensitivity MCQs Biology with Answers should focus on the relationship between IgE and histamine. IgE is the antibody most strongly associated with allergic reactions, while histamine is released mainly by mast cells during an allergic response. Allergy and Hypersensitivity MCQs Biology with Answers helps aspirants understand why anti-histamines are used to reduce allergy symptoms. Anti-histamines block the action of histamine and provide relief from symptoms such as itching, sneezing, nasal discharge, and skin rashes. In severe allergic reactions such as anaphylaxis, adrenaline may be used because it quickly opens airways, reduces swelling, and supports blood pressure. Allergy and Hypersensitivity MCQs Biology with Answers is therefore important for understanding both theory and practical medical response.

Allergy and Hypersensitivity MCQs Biology with Answers also includes different allergic conditions such as asthma, hay fever, skin allergy, food allergy, and drug allergy. Asthma may involve allergic inflammation of the airways, leading to wheezing, coughing, chest tightness, and difficulty in breathing. Hay fever, also called allergic rhinitis, is caused by hypersensitivity to allergens such as pollen, dust, or pollutants. Allergy and Hypersensitivity MCQs Biology with Answers helps aspirants connect these conditions with exaggerated immune responses rather than infections. This distinction is important because allergy is not caused by pathogens like bacteria or viruses, but by the immune system reacting strongly to otherwise harmless substances.

Hypersensitivity reactions are another key part of Allergy and Hypersensitivity MCQs Biology with Answers. Hypersensitivity may be immediate or delayed depending on the immune mechanism involved. Immediate hypersensitivity is commonly associated with IgE antibodies, mast cells, and histamine release. Allergy and Hypersensitivity MCQs Biology with Answers helps aspirants identify how allergic reactions differ from autoimmune disorders. In allergy, the immune system reacts excessively to external allergens, while in autoimmune diseases, the immune system attacks the body’s own cells. This difference is important for aspirants because both topics are often discussed together under immunity.

Allergy and Hypersensitivity MCQs Biology with Answers should also be studied with the concept of inflammation. Inflammation is a protective response of the body, but in allergic reactions, it may become excessive. Redness, swelling, heat, pain, and itching are common features of inflammatory responses. Allergy and Hypersensitivity MCQs Biology with Answers helps aspirants understand that mast cells, basophils, antibodies, cytokines, and chemical mediators are all involved in allergic inflammation. Aspirants should also remember that steroids may be used to reduce strong inflammatory reactions, while anti-histamines are used to control histamine-related symptoms.

For effective revision, Allergy and Hypersensitivity MCQs Biology with Answers should be studied through short notes, flowcharts, comparison tables, and concept maps. Aspirants can prepare a simple flow: allergen exposure, IgE production, mast cell sensitization, repeated exposure, histamine release, and allergy symptoms. Allergy and Hypersensitivity MCQs Biology with Answers becomes easier when aspirants connect each term with its role.

IgE is linked with allergy, mast cells with histamine release, anti-histamines with symptom control, and adrenaline with emergency allergic reactions. Allergy and Hypersensitivity MCQs Biology with Answers also helps aspirants revise the difference between innate immunity, acquired immunity, allergy, hypersensitivity, and autoimmunity.

A strong understanding of Allergy and Hypersensitivity MCQs Biology with Answers improves exam confidence because many biology questions are based on direct facts and conceptual differences. Aspirants should avoid confusing allergy with infectious disease, antigen with allergen, IgE with IgG, and hypersensitivity with normal immunity. Allergy and Hypersensitivity MCQs Biology with Answers also builds awareness about health practices such as avoiding known allergens, keeping surroundings clean, seeking medical advice for severe allergy, and not ignoring breathing difficulty during allergic attacks.

Allergy and Hypersensitivity MCQs Biology with Answers:

1. Identify the wrong statement with reference to immunity.

A. When ready-made antibodies are directly given, it is called passive immunity.
B. Active immunity is quick and gives full response.
C. Foetus receives some antibodies from mother; it is an example of passive immunity.
D. When exposed to antigen, living or dead, antibodies are produced in the host’s body. It is called active immunity.

Answer: B. Active immunity is quick and gives full response.

Explanation: Active immunity develops when the body produces antibodies in response to an antigen. It is not quick, but it is usually long-lasting.

2. ______ quickly reduce the symptoms of allergy.

A. Serotonin
B. Heparin
C. Adrenaline
D. Histamine

Answer: C. Adrenaline

Explanation: Adrenaline rapidly reduces severe allergic symptoms by opening airways, reducing swelling, and maintaining heart function and blood pressure.

3. Select the correct match.
   Lymphocyte : antibodies :: Basophil : _____.

A. Heparin
B. Fibrin
C. Globulin
D. Anti-histamine

Answer: A. Heparin

Explanation: Basophils release heparin and histamine. Heparin prevents blood from clotting too quickly.

4. This is the correct statement for IgE.

A. Inhibits the secretion of histamine and serotonin from mast cells
B. Does not stimulate B cells
C. Gives immune response to allergens
D. This antibody is received from the mother to the foetus through placenta during pregnancy

Answer: C. Gives immune response to allergens

Explanation: Immunoglobulin E, IgE, is involved in allergic reactions. It is produced when the immune system reacts to allergens.

5. Which of the following disease is caused by allergic reactions?

A. Leprosy
B. Typhoid
C. Asthma
D. Tetanus

Answer: C. Asthma

Explanation: Asthma can be caused by allergic reactions. Allergy is an abnormal immune response to foreign substances such as dust, pollen, or certain foods.

6. Select the incorrect statement with respect to acquired immunity.

A. Acquired immunity is non-specific type of defense present at the time of birth.
B. Primary response is produced when our body encounters a pathogen for the first time.
C. Anamnestic response is elicited on subsequent encounters with the same pathogen.
D. Anamnestic response is due to memory of first encounter.

Answer: A. Acquired immunity is non-specific type of defense present at the time of birth.

Explanation: Acquired immunity is specific and is not present at birth. It develops after exposure to antigens.

7. Which of the following statements is true regarding acquired immunity?

A. Acquired immunity is present at the time of birth
B. Anamnestic response is a primary immune response
C. Innate immunity is a specific type of acquired immunity
D. Acquired immunity is not present at the time of birth

Answer: D. Acquired immunity is not present at the time of birth

Explanation: Acquired immunity develops after exposure to pathogens or vaccination. It is specific and has memory.

8. In the context of autoimmune disorders, which of the following statements is correct?

Statement I: Autoimmune disorder is a condition where body defence mechanism recognizes its own cells as foreign bodies.
Statement II: Rheumatoid arthritis is a condition where body does not attack self cells.

A. Statement I is incorrect but Statement II is correct
B. Both Statement I and Statement II are correct
C. Both Statement I and Statement II are incorrect
D. Statement I is correct but Statement II is incorrect

Answer: D. Statement I is correct but Statement II is incorrect

Explanation: Autoimmune disorders occur when the immune system attacks the body’s own cells. Rheumatoid arthritis is an autoimmune disorder in which the body attacks self tissues.

9. When a person is injected with globulin against hepatitis, what type of immunity is acquired?

A. Artificially acquired passive immunity
B. Artificially acquired active immunity
C. Naturally acquired active immunity
D. Naturally acquired passive immunity

Answer: A. Artificially acquired passive immunity

Explanation: Injection of ready-made globulin antibodies against hepatitis provides artificially acquired passive immunity.

10. Which cells are related to inflammatory reactions and immediate hypersensitivity?

A. Mast cells
B. Plasma cells
C. Fibroblast cells
D. All of these

Answer: A. Mast cells

Explanation: Mast cells are involved in inflammatory reactions and immediate hypersensitivity allergic responses.

11. Match the following types of immunity with their descriptions.

A. Natural active immunity
B. Natural passive immunity
C. Artificial active immunity
D. Artificial passive immunity

Descriptions:
I. Develops due to vaccination
II. Anti-rabies serum
III. Acquired after smallpox infection
IV. Transferred from mother to child

Options:

A. A-III, B-IV, C-II, D-II
B. A-IV, B-III, C-I, D-I
C. A-III, B-I, C-IV, D-II
D. A-III, B-IV, C-I, D-II

Answer: D. A-III, B-IV, C-I, D-II

Explanation: Natural active immunity develops after natural infection, natural passive immunity is transferred from mother to child, artificial active immunity develops through vaccination, and artificial passive immunity is obtained through ready-made antibodies such as anti-rabies serum.

12. Match the barriers with their corresponding components.

List-I:
A. Cellular barrier
B. Cytokine barrier
C. Physical barrier
D. Physiological barrier

List-II:
I. Interferons
II. Mucus
III. Neutrophils
IV. HCl in gastric juice

Options:

A. A-II, B-III, C-IV, D-I
B. A-II, B-III, C-I, D-IV
C. A-III, B-IV, C-II, D-I
D. A-III, B-I, C-II, D-IV

Answer: D. A-III, B-I, C-II, D-IV

Explanation: Cellular barriers include neutrophils, cytokine barriers include interferons, physical barriers include mucus, and physiological barriers include HCl in gastric juice.

13. Which of the following elements is important to maintain the structure of immunoglobulin?

A. P
B. Fe
C. S
D. Ca

Answer: C. S

Explanation: Immunoglobulins contain disulphide bonds between polypeptide chains. Sulphur helps maintain the structure of immunoglobulins.

14. Grafted kidney may be rejected in a patient due to

A. Innate immune response
B. Humoral immune response
C. Cell-mediated immune response
D. Passive immune response

Answer: C. Cell-mediated immune response

Explanation: Graft rejection is mainly caused by cell-mediated immune response involving T-lymphocytes.

15. The affinity of an antibody can be determined by measuring

A. Its concentration
B. The valency of antigen binding
C. The amount of antibody bound at various antigen concentrations
D. Its ability to neutralize bacterial toxins

Answer: C. The amount of antibody bound at various antigen concentrations

Explanation: Antibody affinity can be determined by measuring how much antibody binds to antigen at different antigen concentrations.

16. What is true about T-lymphocytes in mammals?

A. There are three main types: cytotoxic T-cells, helper T-cells, and suppressor T-cells
B. These originate in lymphoid tissues
C. They scavenge damaged cells and cellular debris
D. These are produced in the thyroid

Answer: A. There are three main types: cytotoxic T-cells, helper T-cells, and suppressor T-cells

Explanation: T-lymphocytes are produced in bone marrow and mature in the thymus. They are involved in cell-mediated immunity.

17. The treatment of snake-bite by antivenom is an example of

A. Artificially acquired active immunity
B. Artificially acquired passive immunity
C. Naturally acquired passive immunity
D. Specific natural immunity

Answer: B. Artificially acquired passive immunity

Explanation: Antivenom contains ready-made antibodies and provides immediate protection, so it is an example of artificially acquired passive immunity.

18. Which one of the following diseases is due to an allergic reaction?

A. Enteric fever
B. Skin cancer
C. Goitre
D. Hay fever

Answer: D. Hay fever

Explanation: Hay fever, also called allergic rhinitis, is caused by allergic reaction to substances such as dust, pollen, and pollutants.

19. Antigens are present

A. Inside the cytoplasm
B. On the nuclear membrane
C. Inside the nucleus
D. On the cell surface

Answer: D. On the cell surface

Explanation: Antigens are commonly present on the cell surface and interact with antibodies or immune cells.

20. In higher vertebrates, the immune system can distinguish self-cells and non-self. If this property is lost due to genetic abnormality and it attacks self-cells, then it leads to

A. Active immunity
B. Allergic response
C. Graft rejection
D. Autoimmune disease

Answer: D. Autoimmune disease

Explanation: Autoimmune disease occurs when the immune system fails to distinguish self from non-self and attacks the body’s own cells.

21. What does the letter T in T-lymphocyte refer to?

A. Thymus
B. Thyroid
C. Thalamus
D. Tonsil

Answer: A. Thymus

Explanation: The letter T in T-lymphocyte refers to thymus, where T-cells mature.

22. The use of anti-histamines and steroids provides quick relief from which condition?

A. Headache
B. Allergy
C. Nausea
D. Cough

Answer: B. Allergy

Explanation: Anti-histamines and steroids are used to provide relief from allergic reactions.

23. What is the primary role of globulins contained in human blood plasma?

A. Clotting of blood
B. Defense mechanisms of the body
C. Osmotic balance of body fluids
D. Oxygen transport in the blood

Answer: B. Defense mechanisms of the body

Explanation: Globulins in blood plasma are involved in defense mechanisms. Some globulins act as antibodies.

24. During an allergic reaction with symptoms like sneezing, watery eyes, running nose, and difficulty in breathing, which type of antibody is produced?

A. IgE
B. IgA
C. IgG
D. IgM

Answer: A. IgE

Explanation: IgE antibodies are produced during allergic reactions and are responsible for immediate hypersensitivity responses.

25. Which of the following act as an antigen but do not induce antibody production?

A. Haustra
B. Histones
C. Haptens
D. None of these

Answer: C. Haptens

Explanation: Haptens can react with antibodies but cannot induce antibody production unless attached to a larger carrier molecule.

26. In blood agglutination, what does it indicate when blood in a test tube clumps together?

A. Antibodies are present in plasma
B. Antigens are present on RBC
C. Antigens are present in plasma
D. Antibodies are present on RBC

Answer: B. Antigens are present on RBC

Explanation: Agglutination occurs due to antigen-antibody reaction. Blood clumping indicates the presence of specific antigens on red blood cells.

27. Identify the factors involved in the second line of defence.

Factors:

A. Skin
B. Complement proteins
C. Mucus
D. Phagocytes
E. Saliva
F. Tears
G. Inflammation
H. Stomach acid
I. Natural killer cells

Options:

A. B, D, G and I
B. B, C, E and I
C. D, F, H and I
D. C, E, G and H

Answer: A. B, D, G and I

Explanation: The second line of defence includes non-specific internal defence mechanisms such as complement proteins, phagocytes, inflammation, and natural killer cells. Skin, mucus, saliva, tears, and stomach acid are mainly part of the first line of defence.

 

28. Identify the monomer forms of the antibodies among the following groups.

A. IgA, IgD, IgE
B. IgG, IgA, IgM
C. IgG, IgA, IgE
D. IgD, IgE, IgG

Answer: D. IgD, IgE, IgG

Explanation: IgD, IgE, and IgG are commonly found as monomers. IgM is usually pentameric, while IgA may occur as a dimer in secretions.

29. Match the types of immunity listed in Column-I with the examples listed in Column-II.

Column-I:
A. Natural active immunity
B. Artificial passive immunity
C. Artificial active immunity
D. Natural passive immunity

Column-II:
p. Not used here
q. From mother to foetus through placenta
r. Injection of antiserum to travellers
s. Fighting infection naturally
t. Induced by vaccination

Options:

A. A-t, B-s, C-r, D-p
B. A-s, B-t, C-q, D-r
C. A-s, B-r, C-t, D-q
D. A-p, B-q, C-r, D-t

Answer: C. A-s, B-r, C-t, D-q

Explanation: Natural active immunity develops by fighting infection naturally, artificial passive immunity is obtained by antiserum injection, artificial active immunity is induced by vaccination, and natural passive immunity is transferred from mother to foetus through the placenta.

30. The progenitors that are formed in bone marrow and differentiated elsewhere are:

A. Pre-NK cell
B. Pre-erythroblast
C. Pre-T cell
D. Myeloblast

Answer: C. Pre-T cell

Explanation: Pre-T cells are progenitors of T-lymphocytes formed in the bone marrow. They later mature in the thymus.

 

 

Conclusion on Allergy and Hypersensitivity MCQs Biology with Answers

In conclusion, Allergy and Hypersensitivity MCQs Biology with Answers is a valuable topic for aspirants who want to master immunity-related concepts in a simple and organized manner. It improves understanding of allergens, IgE antibodies, mast cells, histamine, inflammation, asthma, hay fever, anti-histamines, steroids, and adrenaline. Allergy and Hypersensitivity MCQs Biology with Answers also helps aspirants connect textbook knowledge with real-life allergic conditions. With consistent revision, Allergy and Hypersensitivity MCQs Biology with Answers can help aspirants improve accuracy, speed, and confidence in biology examinations.